/**
 * $RCSfile$
 * $Revision$
 * $Date$
 *
 * Copyright 2003-2007 Jive Software.
 *
 * All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.jivesoftware.smackx.packet;

import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;

import org.jivesoftware.smack.packet.PacketExtension;

/**
 * Represents timestamp information about data stored for later delivery. A
 * DelayInformation will always includes the timestamp when the packet was
 * originally sent and may include more information such as the JID of the
 * entity that originally sent the packet as well as the reason for the delay.
 * <p>
 * 
 * For more information see <a
 * href="http://xmpp.org/extensions/xep-0091.html">XEP-0091</a> and <a
 * href="http://xmpp.org/extensions/xep-0203.html">XEP-0203</a>.
 * 
 * @author Gaston Dombiak
 */
public class DelayInformation implements PacketExtension {

	/**
	 * Date format according to the obsolete XEP-0091 specification. XEP-0091
	 * recommends to use this old format for date-time instead of the one
	 * specified in XEP-0082.
	 * <p>
	 * Date formats are not synchronized. Since multiple threads access the
	 * format concurrently, it must be synchronized externally.
	 */
	public static final DateFormat XEP_0091_UTC_FORMAT = new SimpleDateFormat(
			"yyyyMMdd'T'HH:mm:ss");
	static {
		XEP_0091_UTC_FORMAT.setTimeZone(TimeZone.getTimeZone("UTC"));
	}

	private Date stamp;
	private String from;
	private String reason;

	/**
	 * Creates a new instance with the specified timestamp.
	 * 
	 * @param stamp
	 *            the timestamp
	 */
	public DelayInformation(Date stamp) {
		super();
		this.stamp = stamp;
	}

	/**
	 * Returns the JID of the entity that originally sent the packet or that
	 * delayed the delivery of the packet or <tt>null</tt> if this information
	 * is not available.
	 * 
	 * @return the JID of the entity that originally sent the packet or that
	 *         delayed the delivery of the packet.
	 */
	public String getFrom() {
		return from;
	}

	/**
	 * Sets the JID of the entity that originally sent the packet or that
	 * delayed the delivery of the packet or <tt>null</tt> if this information
	 * is not available.
	 * 
	 * @param from
	 *            the JID of the entity that originally sent the packet.
	 */
	public void setFrom(String from) {
		this.from = from;
	}

	/**
	 * Returns the timestamp when the packet was originally sent. The returned
	 * Date is be understood as UTC.
	 * 
	 * @return the timestamp when the packet was originally sent.
	 */
	public Date getStamp() {
		return stamp;
	}

	/**
	 * Returns a natural-language description of the reason for the delay or
	 * <tt>null</tt> if this information is not available.
	 * 
	 * @return a natural-language description of the reason for the delay or
	 *         <tt>null</tt>.
	 */
	public String getReason() {
		return reason;
	}

	/**
	 * Sets a natural-language description of the reason for the delay or
	 * <tt>null</tt> if this information is not available.
	 * 
	 * @param reason
	 *            a natural-language description of the reason for the delay or
	 *            <tt>null</tt>.
	 */
	public void setReason(String reason) {
		this.reason = reason;
	}

	public String getElementName() {
		return "x";
	}

	public String getNamespace() {
		return "jabber:x:delay";
	}

	public String toXML() {
		StringBuilder buf = new StringBuilder();
		buf.append("<").append(getElementName()).append(" xmlns=\"")
				.append(getNamespace()).append("\"");
		buf.append(" stamp=\"");
		synchronized (XEP_0091_UTC_FORMAT) {
			buf.append(XEP_0091_UTC_FORMAT.format(stamp));
		}
		buf.append("\"");
		if (from != null && from.length() > 0) {
			buf.append(" from=\"").append(from).append("\"");
		}
		buf.append(">");
		if (reason != null && reason.length() > 0) {
			buf.append(reason);
		}
		buf.append("</").append(getElementName()).append(">");
		return buf.toString();
	}

}
